They don't though, Android is clearly ahead in AI integration (even Samsung are running TV ads mocking iPhones AI capability) yet still iPhones sales are breaking records - the majority of their phone buyers still prefer an iPhone over an AI capable other phone.
They can take their time to develop AI integration that others can't deploy - 'secure/private', deep integration with iCloud, location services, processing on device etc. that will provide the product moat to increase sales.